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This is a 8 channel relay box that the input connect to a controller allow it to control large loads like home appliances.

I'm using this relay box for a snooker centre to control snooker table lamps. The lamps consists of 6 pieces 20W and 3 pieces 10W fluorescent lamps, total of power consumption is 150W per table. Picture below shows the snooker table lights for the snooker centre.

This project eliminate the use of an expensive Wifi/Network Shield but still able to control home appliances from any where. You may already own a wireless router which support OpenWRT or else you can get a very cheap wireless router such as WR703N for this project.

In order to eliminate install many packages on the router, I am using HTML and Javascript for the web interface, while hardware interface is using Lua which is come with OpenWRT. The whole process is just install a serial driver (see step below) to make the instruction simple & keep the router free of resources.

You can also download the beta version dated 2012/03/30, but I didn't test it.

Make sure backup all data before firmware upgrade. After upgrade the firmware, the DNS-320 performance become very slow. I had to re-format the HDD and install software again in order to solve the problem.

Client mode uses its wireless connection as the WAN interface, and shares the internet connection only to the LAN ports. It is not seen as an access point by laptops or other computers scanning for AP's and does not accept wireless connections from client devices.

As shown in figure below, the new SSID (wwan) cannot be seen by other client devices nor accept wireless connection from client devices. Therefore the client devices (Notebook3 and Notebook4) must connect to the Wifi router using network cable.

Additional fun_plug packages (eg. LAMP, Transmission client, etc) can be install/uninstall after installing fun_plug. Article below show you how to install additional packages to fun_plug 0.7. You should read this article if you want to know more about fun_plug.

If you are using Arduino (or any other TTL device) to control 4 channel relays or more, I would suggest to use ULN2803 Line Driver instead of Transistors or FETs. You can use ULN2003 which is much more cheaper if you plan to use not more than 7 channel relays.

The ULN2803 Integrated Circuit (IC) is a "Eight-way Line Driver". It allows you to interface TTL signals (5v) with higher voltage/current (50V/500ma) loads.

As shown in figure 1 and figure 2, an Arduino is control 8 relays, one using ULN2803 line driver and the other one using transistors, both circuit are equivalent.